More fish and what kind

Currently I have a 20 gallon tank with 2 silver dollors,3 black skirt tetras and 2 black mollies.Can I add more?If so what fish are compatible with my current fish.

 

Honestly your silver dollar isn't compatible with your fish tank. I would return/rehome them. They can get to the size of a dinner plate and it is also a schooling fish.

I would add 3 more black skirts to make a proper school.
You can add another school of tetra if you want.

 

If I take him back to the fish store what are some colorful fish that would be good with my other fish

 

neons, cardinals, celestial pearl danios, ember tetras, rasboras....

If I were you, I would go to your LFS/Chain store and see what fish appeals to you. Take the names down, come back home and research if they will be compatible with your tank and current stock.

Also, Silver dollars will be eating your plants in your aquarium.

 

Ok thanks. I'm might get some celestial pearl danios.

 

Ok thanks. I'm might get some celestial pearl danios.

Those are nice...especially in a heavily planted tank.